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The North Atlantic region experienced abrupt high-amplitude cooling at the onset of the Younger Dryas stadial. However, due to chronological uncertainties in the available terrestrial records it is unclear whether terrestrial ecosystem response to this event was instantaneous and spatially synchronous, or whether regional or time-transgressive lags existed. Here we use new palynological results from a robustly dated lake sediment sequence retrieved from lake Hämelsee (north Germany) to show that vegetation change started at 12,820 cal. yr BP, concurrent with the onset of changes in local climate. A comparison of the Hämelsee results to a compilation of precisely dated palynological records shows instant and, within decadal-scale dating uncertainty, synchronous response of the terrestrial plant community to Late-Glacial climate change across northwest Europe. The results indicate that the environmental impact of climate cooling was more severe than previously thought and illustrates the sensitivity of natural terrestrial ecosystems to external forcing.

Approximately 74 thousand years ago (ka), the Toba caldera erupted in Sumatra. Since the magnitude of this eruption was first established, its effects on climate, environment and humans have been debated. Here we describe the discovery of microscopic glass shards characteristic of the Youngest Toba Tuff-ashfall from the Toba eruption-in two archaeological sites on the south coast of South Africa, a region in which there is evidence for early human behavioural complexity. An independently derived dating model supports a date of approximately 74 ka for the sediments containing the Youngest Toba Tuff glass shards. By defining the input of shards at both sites, which are located nine kilometres apart, we are able to establish a close temporal correlation between them. Our high-resolution excavation and sampling technique enable exact comparisons between the input of Youngest Toba Tuff glass shards and the evidence for human occupation. Humans in this region thrived through the Toba event and the ensuing full glacial conditions, perhaps as a combined result of the uniquely rich resource base of the region and fully evolved modern human adaptation.

Supplemental material, Supplementary_Data_File_2 for A cryptotephra record from the Lake Victoria sediment core record of Holocene palaeoenvironmental change by Christine S Lane, Catherine Martin-Jones and Thomas C Johnson in The Holocene

Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters.

This paper introduces the aims and scope of the RESET project (. RESponse of humans to abrupt Environmental Transitions), a programme of research funded by the Natural Environment Research Council (UK) between 2008 and 2013; it also provides the context and rationale for papers included in a special volume of Quaternary Science Reviews that report some of the project's findings. RESET examined the chronological and correlation methods employed to establish causal links between the timing of abrupt environmental transitions (AETs) on the one hand, and of human dispersal and development on the other, with a focus on the Middle and Upper Palaeolithic periods. The period of interest is the Last Glacial cycle and the early Holocene (c. 100-8 ka), during which time a number of pronounced AETs occurred. A long-running topic of debate is the degree to which human history in Europe and the Mediterranean region during the Palaeolithic was shaped by these AETs, but this has proved difficult to assess because of poor dating control. In an attempt to move the science forward, RESET examined the potential that tephra isochrons, and in particular non-visible ash layers (cryptotephras), might offer for synchronising palaeo-records with a greater degree of finesse. New tephrostratigraphical data generated by the project augment previously-established tephra frameworks for the region, and underpin a more evolved tephra 'lattice' that links palaeo-records between Greenland, the European mainland, sub-marine sequences in the Mediterranean and North Africa. The paper also outlines the significance of other contributions to this special volume: collectively, these illustrate how the lattice was constructed, how it links with cognate tephra research in Europe and elsewhere, and how the evidence of tephra isochrons is beginning to challenge long-held views about the impacts of environmental change on humans during the Palaeolithic. © 2015 Elsevier Ltd., RESET was funded through Consortium Grants awarded by the Natural Environment Research Council, UK, to a collaborating team drawn from four institutions: Royal Holloway University of London (grant reference NE/E015905/1), the Natural History Museum, London (NE/E015913/1), Oxford University (NE/E015670/1) and the University of Southampton, including the National Oceanography Centre (NE/01531X/1). The authors also wish to record their deep gratitude to four members of the scientific community who formed a consultative advisory panel during the lifetime of the RESET project: Professor Barbara Wohlfarth (Stockholm University), Professor Jørgen Peder Steffensen (Niels Bohr Institute, Copenhagen), Dr. Martin Street (Romisch-Germanisches Zentralmuseum, Neuwied) and Professor Clive Oppenheimer (Cambridge University). They provided excellent advice at key stages of the work, which we greatly valued. We also thank Jenny Kynaston (Geography Department, Royal Holloway) for construction of several of the figures in this paper, and Debbie Barrett (Elsevier) and Colin Murray Wallace (Editor-in-Chief, QSR) for their considerable assistance in the production of this special volume.

The discovery of sites preserving tephra layers from multiple volcanic centres is key to constructing a single European tephrostratigraphic framework for the Late Quaternary. Until now, the tephrostratigraphy of Europe has been divided into two halves: sites in the North Atlantic and northern Europe regions link the Icelandic, Eifel, and the Massif Central volcanic histories; whilst sites in southern Europe record the sequence of tephra layers produced by circum-Mediterranean volcanic provinces. The missing link, able to tie together these two halves, is found in the tephrostratigraphic record of Lake Bled, Slovenia.Lake Bled, in the Julian Alps, Slovenia, holds a high resolution multi-proxy palaeoenvironmental archive for the Lateglacial of south-central Europe. Cryptotephra investigations have revealed three tephra layers: two closely spaced within Younger Dryas stadial sediments and one shortly after the start of the Bølling-Allerød interstadial warming. Two of the tephra layers (Bld_T120 and Bld_T240) are of Campanian origin and are correlated to deposits of the Pomici Principali (PP) and Neapolitan Yellow Tuff (NYT) eruptions, respectively. The third layer (Bld_T122) correlates to the Icelandic Vedde Ash (VA), extending the known fallout of this widespread marker layer farther to the southeast.The Lake Bled record also allows the stratigraphic relationship and relative ages of the VA and the PP eruption to be discerned for the first time. Whilst existing numerical age estimates for these two deposits are indistinguishable within errors, their close occurrence in the same lacustrine sediment sequence shows that the VA was erupted shortly prior to the PP eruption.The tephrostratigraphy of Lake Bled developed here helps us to tie together regional volcanic stratigraphies into a broader, continental-scale lattice of sites, with the potential to allow the transfer of dates between remote sequences and the construction of relative chronologies, beneficial in particular for environmental and archaeological research. © 2011 Elsevier Ltd.

The ∼74 ka BP Youngest Toba Tuff (YTT), from the largest known Quaternary volcanic eruption, has been found for the first time as a non-visible (crypto-) tephra layer within the Billa Surgam caves, southern India. The occurrence of the YTT layer in Charnel House Cave provides the first calendrical age estimate for this much debated Pleistocene faunal sequence and demonstrates the first successful application of cryptotephrochronology within a cave sequence. The YTT layer lies ∼50 cm below a major sedimentological change, which is related to global cooling around the MIS 5 to MIS 4 transition. Using this isochronous event layer the Billa Surgam Cave record can be directly correlated with other archaeological sites in peninsular India and palaeoenvironmental archives across southern Asia. © 2011 Elsevier Ltd.

The Laacher See eruption (LSE) in Germany ranks among Europe’s largest volcanic events of the Upper Pleistocene (1,2). Although tephra deposits of the LSE represent an important isochron for the synchronization of proxy archives at the Late Glacial to Early Holocene transition (3), uncertainty in the age of the eruption has prevailed (4). Here we present dendrochronological and radiocarbon measurements of subfossil trees that were buried by pyroclastic deposits that firmly date the LSE to 13,006 ± 9 calibrated years before present (bp; taken as ad 1950), which is more than a century earlier than previously accepted. The revised age of the LSE necessarily shifts the chronology of European varved lakes (5,6) relative to the Greenland ice core record, thereby dating the onset of the Younger Dryas to 12,807 ± 12 calibrated years bp, which is around 130 years earlier than thought. Our results synchronize the onset of the Younger Dryas across the North Atlantic–European sector, preclude a direct link between the LSE and Greenland Stadial-1 cooling (7), and suggest a large-scale common mechanism of a weakened Atlantic Meridional Overturning Circulation under warming conditions (8–10).

Efforts to date the oldest modern human fossils in eastern Africa, from Omo-Kibish1-3 and Herto4,5 in Ethiopia, have drawn on a variety of chronometric evidence, including 40Ar/39Ar ages of stratigraphically associated tuffs. The ages that are generally reported for these fossils are around 197 thousand years (kyr) for the Kibish Omo I3,6,7, and around 160-155 kyr for the Herto hominins5,8. However, the stratigraphic relationships and tephra correlations that underpin these estimates have been challenged6,8. Here we report geochemical analyses that link the Kamoya's Hominid Site (KHS) Tuff9, which conclusively overlies the member of the Omo-Kibish Formation that contains Omo I, with a major explosive eruption of Shala volcano in the Main Ethiopian Rift. By dating the proximal deposits of this eruption, we obtain a new minimum age for the Omo fossils of 233 �� 22 kyr. Contrary to previous arguments6,8, we also show that the KHS Tuff does not correlate with another widespread tephra layer, the Waidedo Vitric Tuff, and therefore cannot anchor a minimum age for the Herto fossils. Shifting the age of the oldest known Homo sapiens fossils in eastern Africa to before around 200 thousand years ago is consistent with independent evidence for greater antiquity of the modern human lineage10., Leverhulme Trust Cambridge-Africa ALBORADA Research Fund SFI award 13/RC/2092

Funder: NOMIS Stiftung; Id: http://dx.doi.org/10.13039/501100008483, The article presents evidence about the Middle Palaeolithic and Middle to Upper Palaeolithic transition interval in the karst area of the Danube Gorges in the Lower Danube Basin. We review the extant data and present new evidence from two recently investigated sites found on the Serbian side of the Danube River – Tabula Traiana and Dubočka‐Kozja caves. The two sites have yielded layers dating to both the Middle and Upper Palaeolithic and have been investigated by the application of modern standards of excavation and recovery along with a suite of state‐of‐the‐art analytical procedures. The presentation focuses on micromorphological analyses of the caves’ sediments, characterisation of cryptotephra, a suite of new radiometric dates (accelerator mass spectrometry and optically stimulated luminescence) as well as proteomics (zooarchaeology by mass spectrometry) and stable isotope data in discerning patterns of human occupation of these locales over the long term.

Reconstructions of climatic and environmental conditions can contribute to current debates about the factors that influenced early human dispersal within and beyond Africa. Here we analyse a 200,000-year multi-proxy paleoclimate record from Chew Bahir, a tectonic lake basin in the southern Ethiopian rift. Our record reveals two modes of climate change, both associated temporally and regionally with a specific type of human behavior. The first is a long-term trend towards greater aridity between 200,000 and 60,000 years ago, modulated by precession-driven wet-dry cycles. Here, more favorable wetter environmental conditions may have facilitated long-range human expansion into new territory, while less favorable dry periods may have led to spatial constriction and isolation of local human populations. The second mode of climate change observed since 60,000 years ago mimics millennial to centennial-scale Dansgaard-Oeschger cycles and Heinrich events. We hypothesize that human populations may have responded to these shorter climate fluctuations with local dispersal between montane and lowland habitats.

In Central and Eastern Europe, research has been focused on loess associated with a plateau-setting, which preserves distinct and well-developed loess and palaeosol units linked to orbital scale changes. This has led to the view that during the last glacial period the Middle and Lower Danube predominantly experienced dry continental climates and supported steppic environments. However outside of the typical plateau setting, some authors have reported a presence of embryonic palaeosols within loess units suggesting sufficient moisture for short-term pedogenesis, and therefore either large scale moisture delivery systems and/or influence of local climatic and/geomorphic factors. Here the palaeoenvironmental and palaeoclimatic history is reconstructed based on two loess-palaeosol profiles in Slivata, North Bulgaria. The site is located in proximity to both the Carpathian and Balkan Mountains and rest on the Danube river terrace. To understand the timing of sediment deposition and dust fluxes chronological approaches combining quartz optically stimulated luminescence (OSL), feldspar post infrared-infrared stimulated luminescence (pIR-IRSL), and tephra correlation were applied. The results are coupled with high-resolution particle size and magnetic susceptibility analysis to provide an overview of past environmental conditions at the site. Finally, zircon U–Pb ages are used to understand potential changes to sediment delivery patterns, in the context of the site development. The investigated profile at Slivata 2 preserves a loess-palaeosol record spanning 52–30 ka, with a very complex sedimentary sequence that switches between periods of enhanced dust flux and sediment accumulation, and palaeosol development. The Slivata 2 sequence is also punctuated by multiple thin “palaeosol” like units that are interpreted as colluvial “soil” deposits on the basis of sedimentology, provenance, and geochronology, indicating a highly variable and dynamic landscape responding to the surrounding environment. The chronology shows very rapid sediment accumulation at Slivata 1 during LGM, with mass accumulation rates similar to sites in the Carpathian Basin, suggesting strong winds and high sediment supply rates. Yet LGM loess is punctuated by a thin palaeosol, which developed between 20–19 ka. This coincides with a temporary glacial retreat in the Carpathian Mountains and higher moisture availability in Eastern Carpathians, and therefore points to localised influences on loess-palaeosol development. Moreover data from Slivata 1 shows soil development and by extension landscape and climate stabilisation shortly prior to 14 ka. The pre-Holocene onset of pedogenesis at Slivata supports ecological and glacial evidence of weak Younger Dryas from the South Carpathian Mountains. Lastly this paper provides a geochemical analysis of the thin tephra horizon preserved in the Slivata 2 profile, which was correlated to the Cape Riva/Y-2 tephra. Consequently Slivata is the most northerly terrestrial site found to contain this tephra horizon, which has implications for the understanding of the size of the Santorini's Cape-Riva/Y-2 explosion. The identification of the Cape Riva (Y-2) tephra horizon and new remodelled age of 21.92 ± 0.56 cal ka BP provides a new tephrostratigraphic marker for eastern European LGM loess.

Sites in North Africa hold key information for dating the presence of Homo sapiens and the distribution of Middle Stone Age (MSA), Middle Palaeolithic (MP) and Later Stone Age (LSA) cultural activity in the Late Pleistocene. Here we present new and review recently published tephrochronological evidence for five cave sites in North Africa with long MSA/MP and LSA cultural sequences. Four tephra horizons have been identified at the Haua Fteah (Cyrenaica, Libya). They include cryptotephra evidence for the Campanian Ignimbrite (CI) eruption dating to ∼39 ka that allows correlation with other Palaeolithic sequences in the eastern Mediterranean and as far north as Russia. Cryptotephra have also been recorded from the Moroccan sites of Taforalt, Rhafas and Dar es-Soltane 1. At Taforalt the geochemical composition suggests a provenance in the Azores, while examples from Sodmein (Egypt) appear to derive from central Anatolia and another unknown source. In these latter examples chemical compositional data from relevant proximal volcanic centres is currently lacking so the identification of tephra in layers of known age and cultural association provides the first reliable age determinations for distal volcanic events and their geographical extent. The future potential for tephrochronological research in North Africa is also discussed.

Tephrochronology is a widely applied method recognized for its exceptional precision in geologic dating and stratigraphic correlation. Tephra from the ~7.6 kyr B.P. Mount Mazama caldera-forming (”climactic”) eruption have been widely identified and applied as stratigraphic isochrons sediments of northwestern North America, as well as in the Greenland ice core records. Recent findings of a microscopic tephra accumulation, or cryptotephra, from Mazama in Newfoundland indicated that this horizon should also be found in Lake Superior sediments. We present findings that confirm the presence of Mazama ash in two sediment cores from the Lake Superior basin, which indicates its likely presence in the rest of the Laurentian Great Lakes and in deposits throughout much of eastern North America and beyond. The ubiquity of this stratigraphic horizon should be applicable to a higher resolution evaluation of climatological, ecological, and archaeological events during the early- to mid-Holocene thermal maximum throughout much of North America.

Corbetti caldera is the southernmost large volcanic system in Ethiopia, and has been categorized at the highest level of uncertainty in terms of hazard and risk. Until now, the number and frequency of past explosive eruptions at Corbetti has been unknown, due to limited studies of frequently incomplete and patchy outcrop sequences. Here we use volcanic ash layers preserved in sediments from three Main Ethiopian Rift lakes to provide the first detailed record of volcanism for the Corbetti caldera. We show that lake sediments yield more comprehensive, stratigraphically-resolved dossiers of long-term volcanism than often available in outcrop. Our eruptive history for Corbetti spans the last 10 k.y. and reveals eruptions at an average return period of ~900 years. The threat posed by Corbetti has, until now, been underestimated. Future explosive eruptions, similar to those of the past 10 k.y. would blanket nearby Awassa and Shashamene, currently home to ~260,000 people, with pumice fall deposits and would have significant societal impacts. A lake sediment tephrostratigraphic approach shows significant potential for application throughout the East African Rift system, and will be essential to better understanding volcanic hazards in this rapidly developing region.

Numerous volcanoes in the Afar Triangle and adjacent Ethiopian Rift Valley have erupted during the Quaternary, depositing volcanic ash (tephra) horizons that have provided crucial chronology for archaeological sites in eastern Africa. However, late Pleistocene and Holocene tephras have hitherto been largely unstudied and the more recent volcanic history of Ethiopia remains poorly constrained. Here, we use sediments from lakes Ashenge and Hayk (Ethiopian Highlands) to construct the first

© 2015 Elsevier Ltd.The record of Late Quaternary environmental change within the sediments of Meerfelder Maar in the Eifel region of Germany is renowned for its high precision chronology, which is annually laminated throughout the Last Glacial to Interglacial transition (LGIT) and most of the Holocene. Two visible tephra layers are prominent within the floating varve chronology of Meerfelder Maar. An Early Holocene tephra layer, the Ulmener Maar Tephra (~11,000 varve years BP), provides a tie-line of the Meerfelder Maar record to the varved Holocene record of nearby Lake Holzmaar. The Laacher See Tephra provides another prominent time marker for the late Allerød, ~200 varve years before the transition into the Younger Dryas at 12,680 varve years BP. Further investigation has now shown that there are also 15 cryptotephra layers within the Meerfelder Maar LGIT-Holocene stratigraphy and these layers hold the potential to make direct comparisons between the Meerfelder Maar record and other palaeoenvironmental archives from across Europe and the North Atlantic. Most notable is the presence of the Vedde Ash, the most widespread Icelandic eruption known from the Late Quaternary, which occurred midway through the Younger Dryas. The Vedde Ash has also been found in the Greenland ice cores and can be used as an isochron around which the GICC05 and Meerfelder Maar annual chronologies can be compared. Near the base of the annual laminations in Meerfelder Maar a cryptotephra is found that correlates to the Neapolitan Yellow Tuff, erupted from Campi Flegrei in southern Italy, 1200km away. This is the furthest north that the Neapolitan Yellow Tuff has been found, highlighting its importance in the construction of a European-wide tephrostratigraphic framework. The co-location of cryptotephra layers from Italian, Icelandic and Eifel volcanic sources, within such a precise chronological record, makes Meerfelder Maar one of the most important tephrostratotype records for continental Europe during the Last Glacial to Interglacial transition.